Flywheel



J. P. SHELL Feb. 16, 1954 FLYWHEEL Filed Oot 25, 1952 INVENTOR.

JUA/US Q7/1524 BY 2%.?

ATTOP/Vf) Patented Feb. 16, 1954 FLYWHEEL Julius P. Shell, Detroit, Mich, assignor to Douglas Tool Company, a corporation of Michigan Application October 25, 1952, Serial No. 316,847

2 Claims.

This invention relates to fly-wheels for outboard motors and in particular to a variable torque compensating tunable fiy-wheel for eliminating the vibration incident to' variations of angular velocity of the crankshaft and associated parts such as in a fixed radial engine.

wheels have long depended on mass to perform their function especially in relation to dampening vibration. In some instances mass can be a commercially employed without limitation such as in stationary steam engines, whereas in other instances, mass is the first commercial limitation such as in portable marine outboard motors.

' With the foregoing in view, the primary object of the invention is to provide a relatively light fly-wheel, articularly suited for outboard motors, which is capable of dampening the vibration incident to variations in crankshaft angular velocity by its design rather than its mass. 7 An object of the invention is to provide a twopiece fly-wheel composed of a center disc portion and a floating outer ring portion so integrated as to be capable of different angular velocities during minute periods of time.

' An object of the invention is to provide a slippable spring pressed frictional engagement between the disc portion and the floating ring por tion so as to cushion-wise impose the movement of one portion on the other during different angular movement of one portion relative to the other.

An object of the invention is to provide studs in one portion and arcuate slots in the other portion surrounding the studs in non-contacting r a whole thereby eliminating transfer of vibra- .tion to the-object on which the engine'is mounted. object of the invention is to provide flexible studs which absorb initial angular velocity variations between the two portions.

, An object of the invention is to provide spring contacting one portion with greater resistance than the frictional resistance between the portions so as to initially flex the studs when one portion moves relative to the other and to subsequently slide the springs relative to the portion on which they bear.

An object of the invention is to provide a fly-wheel which can be tuned by varying the stud length, diameter, hardness, ductility, etc., and by varying the spring size, force, and area of surface bearing on a portion.

An object of the invention is to provide a selftuning fly-wheel which is easy and economical to manufacture, simple in design and construction, durable and fool roof in use, and which .can readily be mounted'on any type or style of engine.

These and other objects of the invention will become apparent by reference to the following description of a tunable, self compensating flywheel embodying the invention taken in connection with the accompanying drawing in which:

Fig. 1 is a top plan view of the device.

Fig. 2 is a cross-sectional view taken on the line 2--2 of Fig. 1; and

Fig. 3 is a fragmentary sectional view showing a modification of the device.

Referring now to the drawing wherein like numerals refer to like and corresponding parts throughout the several views, the fly-wheel disclosed therein to illustrate the invention comprises a hub portion l0 adapted to be bolted to a. crankshaft H by nuts l2 and bolts 13 or otherwise suitably secured thereto as by splining or keying; a disc portion l4 emanating radially from the hub In; a circumferential, annular, or segmental arcuate ridge 15 on the disc portion it; studs 16 embedded in the disc portion I t cantilevered or projecting outwardly from the disc portion M having snap-ring grooves ll adjacent their ends 20; :a tire-like ring l8 having a circumferential, annular, or segmental arcuate channel 19 adapted to mate with the ridge 15 so that the ridge I5 is received within the chan- ,/nel I9 radially positioning the disc portion 14 .and the ring portion 18 so that they are conwalls of the ring portion I8 defining the slots 2| 'studs l6. It cannow be seen that the ring portion [8 is capable of limited pivotal movement relative to the disc portion l4 and vice-versa with the ridge I5 and mating channel [9 maintaining the parts concentric with each other.

The disc portion [4 and ring portion l8 are spring pressed together in frictional engagement such as by the spring washers 22 which are secured 'to :thenyends 2!] 1 of therstuds i 6 by the snap ring 23. The spring-washers. 22 bear against the ring portion I8 urging the contacting surfaces of the ring portion l8 and disc portion M together in frictional engagement. It can now be seen that free pivotal movement of the ring portion 18 relative to the disc,.portion his restrained by the spring pressedfrictional engagement between the parts.

In operation, with the inventive fly-wheel mounted on the crankshaftof arunning engine, the ring portion I8 rotates on the me-amangular velocity of the crankshaft while the disc portion .Mfollows any angularavelocity variations of ,.the crankshaft. The.v difference. between. the, angu- ,lar .velocities of .the ring. portion ,l8 and. the disc portionv i4 being absorbedby. pivotal, movement .of the disc portion 14. relative to .thering portion l 8 ,as :impeded by. their ,spring, pressedfrictional .engagementwi-th .each other.

An important..feature of the device .is that the springwashers 22 exert a greaterpoundtper ,sq. im pressure on the ringportion |8.-at their. edges. ..;24 .than.does the ring portion launderlthe same .,spring ..load in. turn v.exert.on the disc. portion .44 due tothe .relatively...larg-er. area of. contact between the discaportion J4 vandthe ring, portion. I8. .In other .words, the spring. load on the. -.washers 22 causes thewashers 22 to bite into .the ring-portion 'l8.so that movementisrela- =tively easier between the discportion l4 .and the ring portion. K8,..and. isrel'atively harder between the washers 22 and the ring portion 18... ;;In v thiseconnection thecantilevered shank por- .tions 25 of the studs l6, areadapted .to flex when relative pivotal slidingdmovement occurs. between the disc portion I4 .andthe. ring portion .-.;l8 =but. does .not occur between the washers .22..

and the ring portionl8.

; It. is. also important. to note that .the usual variations in crankshaft. angular velocity are .minute. and that the. cantilevered or projecting stud shank has sufiicientflexibility to,,absorb them. ,Moreover, thesize, resiliency, rigidity," and flexibility of, the stud canbeselected to. suit the .motor, ,-on whichthe inventive. .fiyrwheel is .-mounted. Obviously, the..size, power and. area -of..contact cf thespring are. also selected .to .ob-

.tain the desired resistance betweenthesprings" and the portion on which they bear as well as the portions themselves.

.In the-event that. larger variations in crankshaft..-. angular velocity areencountered ,exceeding the flexibility. ofv .the v studs .1 6, the. ring por .tion .IBiscapable,of,moving .not only relative .to the disc. portion 14 but, also, relative .to the ..washers...22 such..as.. caused by, pre-ignition of .;fuel ..or=.backfiring conditions in the en ine or sudden loading or .unloadingsuch as is, incident .to clutching. and .unclutching in changing, ,gears or direction of drive.

.Undernormaloperating conditions it has been found that. the flexibility of. the studsis, suflicient to allowthe relative .movementbetweenthe parts demandedbythe. variations in crankshaf an uglar elocity wh t e s uddi mete le th. flex ..bi1ity' and..,.hardness.,..are p'ropfly selected and ,apronerly...co-ordinate'd withiihaflmQunt. of, 11

pressure applied in conjunction with the number of studs employed.

Fig. 3 shows a modification of the invention wherein the disc portion and the ring por- 5 tion 3| are movable relative to each other not only angularly but also radially as no mechanical means are employed to locate the por- -tions-radiallyrelative -tdrone .another. The vstuds. 32-1-and 1springs.133are selectedas in the 10 device of Figs. 1 and 2. The angular characteristics of the device of Fig. 3 are the same as in the device of Figs. 1 and 2, however, the ring -portion 3| and the disc portion 30 are free to developr. individualirdynamic balance during rotation;- and, as the ring portion 3| is not impeded by.;mechanically attached parts it is ca- A pable of achieving a position approximating true dynamic balance. As the disc portion 30 is limiteda by attached arts relative to individually 20 achieving dynamic balance, a radial difference ,may..exist. between. the. ring portion 3|..and the ,discportion 3U. vDue,. to..the.factv thatv the. por- ;..tions .are .in. spring pressed. frictional engagement at. theircontacting surfaces, the ring portion. 3| dampenslthe .radial .vibrationjncident to the discportion .30. (.Thestuds .32, flex angularly. and radially .under relativelysmall variationsbetween theportion. and thespring .33 slides relative to. the .ring portion 3I-..on.- which 30 [it bears under increased or larger. variations.

Although. but two embodiments of the. invention have been shown and describedin. detail, it .is obvious. that many changes maybemadein .the. size, shape, .detail andarrangement-of the vvarious elements of .the inventionwithin the scope of theappended claims.

I claim: l. A fly-wheel. for. damping vibration incident to angular velocity variations. of a rotatingv shaft, said fly-wheel comprising adisc portionadapted .to. be secured to said shaft. forangul-ar-move- .ment therewith, anannulardamping ring in frictional engagement with saiddisc.portiomflexible means cantilevered. from said disc portion. and extending through slotsin said ringinnonengaging relation with. said ring, and resilient .means secured to said .fleXible means. clampingly engaging said ring for holdingsaid ring, in slip- .p'able frictional. engagement withsaiddisc portion and with said resilient.means,,..said-resilient means exerting ,a. greater pressure .on. said ring -than saiclring exerts on said disc. portion whereby. relatively. .minor angular velocity variations .of. said shaft. cause limited. relative rotation v of said rin and saiddisc portion via the flexibility of. said flexible means and major angular velocity .yariationseof said shaft .cause said ring to be displaced relatively to both said disc portiorrand said. resilient means. .12.'Affly -wheel asset forth in claim' 1 wherein said disc portion is provided with an outwardly projecting ridge, and said ringis; provided with a mating" groove receiving said' ridge whereby radial displacement of said ring relatively to said disc portion is precluded.

' "JULIUS -P.' SHELL.

;. ie ferences Cited; in the fileofthis patent UNITEDJSTATES- PAT 

